Diaphragm pumps



Jan. 23, 1968 c. QUATREDENIERS ETAL. 3,3

DIAPHRAGM PUMPS Filed Feb. 21, 1966 4 Sheets-Sheet J I nuenlors (VawaeQz/afreaemers W 6 94am) Attorney J 23, 1968 c. QUATREDENIERS ETAL3,364,870

DIAPHRAGM PUMPS Filed Feb. 21, 1966 4 Sheets-Sheet 2 Inventors L /azzaeQumreaeniers 6 f/M/ze/ fibzrot' a 3, 1968 c. QUATREDENIERS ETAL 3,

DEAPHRAUM PUMPS Filed Feb. 21. 1966 4 Sheets-$heet 1963 c. QUATREDENIERSETAL 3,364,870

DIAPHRAGM PUMPS Filed Feb. 21, 1966 4 Sheets-Sheet 4 I n v e n t o r s C/azzae Qua :rea'enzi rs FFFzt/Je/ "Y0 fro? c5 lwyb/-gm 3,364,870Patented Jan. 23, 1968 DIAPHRAGM PUMPS Claude Quatredeniers, Les Lilas,and Michel Noirot,

Chelles, France, assignors to General Motors Corporation, Detroit,Mich., a corporation of Delaware Filed Feb. 21, 1966, Ser. No. 529,044Claims priority, application Great Britain, Mar. 25, 1965, 12,644/65 2Claims. (Cl. 103-150) ABSTRACT OF THE DISCLOSURE A diaphragm fuel pumpin which two coaxial sleeves surround a pressure actuated inlet valve todefine at least one pulsator chamber between the sleeve walls forfavorably affecting pump discharge.

This invention relates to diaphragm pumps and in particular to diaphragmpumps such as are commonly used as fuel pumps for internal combustionengines.

A diaphragm pump according to the invention has a flexible diaphragm theperiphery of which is pressed into sealing engagement with a seat in apump body by means of a valve and seat plate assembly, shaped from sheetmaterial, the periphery of which is pressed into sealing contact withthe diaphragm by a peripheral flange of a pressed sheet metal coverwhich is crimpcd over the pump body adjacent the scat therein.

The valve and seat plate assembly comprises a valve seat plate withinlet and outlet valve ports controlled by movable valve members whichare cngageable with valve seats on the plate; and a sleeve extendsaround one of said valves, preferably the inlet valve, and is sealed atopposite ends to said cover and said seat plate to divide the spacetherebetween into an inlet and an outlet chamber. The sleeve may be ofresilient material the ends of which are clamped between the cover andthe seat plate; or a metal sleeve may be used, one end thereof beingwelded to the cover and the other end being press-fitted on to a bosswhich extends around the valve, a seal ring being interposed between thesleeve and boss.

The pump cover preferably has an opening therein which is incommunication with the inlet chamber, and a filter screen is preferablysecured over said opening by means of a cap which is secured to thecover.

Conveniently the filter screen has a peripheral gasket and also acentral gasket, the latter being a sliding fit on a bolt which extendsthrough the cap and said central gasket and is secured in a nut fixed tothe pump cover so that the cap can be tightened into scaling contactwith the cover, the peripheral gasket being clamped between the cap andcover.

The sleeve, if of resilient material, may be formed at opposite endswith integral inwardly directed flanges which are clamped over oppositeends of a sleeve of rigid material arranged within the resilient sleeve,the body of the resilient sleeve being formed so as to provide betweenthe outer periphery of the rigid sleeve and the inner periphery of theresilient sleeve a plurality of air pockets which, when the pump is inoperation act as pulsator chambers or cells and stabilize the dischargepressure of the pump.

The pump diaphragm is preferably pre-moulded and is clamped between apair of press-fitted cup members either or both of which may be formedof a synthetic plastics material resistant to hydrocarbon fuels.

The diaphragm is preferably arranged for reciprocation by a push rodwhich is slidably mounted in a bore in the pump body, one end of the rodbeing adapted to engage one of said cup members and the other end beingadapted to be engaged by a rotary cam on the engine to which the pump isfitted.

Reference will now be made to the accompanying informal drawings whichillustrate a preferred embodiment of the invention and in which:

FIGURE 1 is a vertical section through a diaphragm pump according to theinvention intended for use as a fuel pump for an internal combustionengine;

FIGURE 2 is a vertical section of a detail of FIG- URE 3;

FIGURE 3 is a plan of FIGURE 1;

FIGURE 4 is a vertical section through a modified diaphragm 3 clampedtherebetween. The upper plate 7 FIGURE 5 is a vertical section through afurther modification of the diaphragm assembly of the pump;

FIGURE 6 is a perspective view of the assembly which constitutes oneform of the pulsator in the pump;

FIGURE 7 is a vertical section through part of a modification of thepump shown in FIGURE 1;

FIGURE 8 is a vertical section of a detail of the seal between the pumpbody and cover; and

FIGURE 9 is a modification of the construction shown in FIGURE 8.

The diaphragm pump shown in FIGURES 1 and 2 comprises a pump body 1(which may be of metal or a syn theric plastics material), in the upperpart of which is an annular seat 2 against which is pressed theperipheral portion of a flexible diaphragm 3, the periphery of thediaphragm being engaged by the peripheral portion of a valve and seatplate assembly 4 which in turn is engaged by the peripheral portion of apump cover 5 which is pressed against the superimposed peripheralportions of the seat plate 4 and diaphragm 3 and is crimped over thepump body adjacent the seat 3, as shown at 6.

The diaphragm 3 is preferably pre-moulded and is clamped at its centralportion between an upper and a lower plate 7, 8 respectively havingintegral therewith central tubular portions 9, 10 which are press-fittedtogether so as to secure the plates 7 and 8 together with the diaphragm3 clamped therebetwcen. The upper plate 7 may be a plastics mouldingresistant to hydrocarbon fuels.

The tubular portion 9 of the upper plate 7 has a longitudinal slottherein extending at diametrically opposed points on the wall of thecylindrical portion and in the slot is slidably engaged a pin 11 whichtransfixes the upper end of a reciprocatory pushrod 14 the lower end ofwhich is adapted to be engaged by a rotary cam 15. The push-rod 14 isslidably mounted in a bore in the pump body 1, the bore being providedwith one or more longitudinal grooves 16 to facilitate the entry oflubricant between the push-rod l4 and the bore in the housing 1.

A seal ring 17 is mounted on the upper end of the push-rod 14 and isseated in an annular groove in the pump body 1 adjacent the upper end ofthe bore in which the push-rod 14 is mounted. The seal ring preventsleakage of lubricant or other liquid along the push-rod 17.

A helical spring 18 is seated at one end on the lower clamp plate 8around the tubular portion 10 thereof and at its other end against anannular seat formed in the pump body 1 adjacent the seat for the sealring 17. The spring is arranged so as normally to press the diaphragm 3upwardly, that is, in a direction to complete a discharge stroke.

Fitted on a reduced diameter portion 19 of the lower end of the push-rod14 is an annular ring 20, of trough section, which forms an abutment forone end of a helical spring 21 the upper end of which is seated in anannular seat 22 formed in the lower part of the pump body 1. The spring21 is arranged so as normally to press the push-rod 14 into engagementwith the cam 15.

The valve and seat assembly 4 comprises a seat plate,

preferably made as a sheet metal stamping, which has therein inletopenings 23 and outlet openings 24. A valve disc 25 overlies the inletopenings 23 and is pressed into engagement with a valve seat on the seatplate 4 by means of a coil spring 26 one end of which engages the valvedisc 25 and the other end of which engages under the heat of a rivet 27which is riveted over on to the other side of the seat plate 4.

Similarly a valve disc 28 overlies the outlet openings 24 and is pressedinto engagement with a valve seat on the seat plate 4 (on the oppositeside thereof to the inlet valve disc) by means of a helical spring 29one end of which engages the valve disc 28 and the other end of whichengages under the head of a rivet 30 the end of which is riveted over onto the other side of the scat plate 4.

The portion of the seat plate 4 on which the inlet valve 25 is mountedis of inverted cup shape and forms a seat for one end of a sleeve 31. ofresilient material such as rubber. the other end of which is engaged bythe cover 5. The ends of the sleeve 31 engage opposite ends of a rigidsleeve 32 so that the ends of the resilient sleeve 31 are clampedagainst the ends of the rigid sleeve 32 by the cover 5 and the seatplate 4.

The resilient sleeve 31 is formed with bulges, as shown in FIGURES 2 and6 so as to provide between the facing walls of it and the rigid sleeve32 one or more cells 33 in which air is trapped by the sealing of theends of the sleeve 3! against the ends of the rigid sleeve 32. The spacewithin the rigid sleeve 32 constitutes an inlet chamber which isseparated by the sleeves 31, 32 from the remainder of the space,constituting the outlet chamber of the pump, between the cover 5 and theseat plate 4.

The cover 5 has therein an opening 34 overlying the inlet valve 25; anda filter disc 35 overlies the opening 34 and is secured to the top ofthe cover by means of a cap 36 which is secured to the cover 5 by a bolt37 which engages in a nut 38 secured to the cover 5. The filter disc 35has a peripheral gasket 39 which is clamped between the cap 36 and thecover 5 and also has a central gasket 40 which is a sealing fit over thebolt 37.

An inlet pipe 41 is secured in the cap 36 and an outlet pipe 42 issecured in the cover 5, the inlet and outlet pipes respectivelycommunicating with the inlet and outlet chambers of the pump.

In the modification of the invention shown in FIGURE 4 the diaphragm 3is clamped between upper and lower plates 50, 51, the assembly of thediaphragm and the plates being secured together and to a tubular member52 having therein diametrically opposed slots 53 to receive the ends ofthe pin 11.

In the modification shown in FIGURE 5 the upper clamp plate 60 isriveted to a lower clamp plate 61 so as to secure therebetween thediaphragm 3, the lower clamp plate 61 being made of plastics materialand having an integral central tubular portion with diametrically opposed slots 62 therein in which can be engaged the ends of the cross pin11.

In operation, rotation of the cam 15 will effect vertical reciprocationof the push-rod 14 so as to reciprocate the pump diaphragm 3, liquidfuel entering by way of the inlet pipe 41 and then passing through thespace within the cap 36, through the litter 35, the inlet opening 34 andthrough the inlet valve 25 to the space below the seat plate 4 and then,during the movement of the diaphragm in the opposite direction passingby way of the outlet valve 28 to the outlet chamber and then through theoutlet pipe 42.

The air cells 33 in the outlet chamber of the pump damp the pulsationresulting from pressure changes during operation of the pump and thusact to stabilise the pump output pressure and increase the fiow rate ofthe pump.

The axial length of the slots in which the pin 11 is movlit ill

4 able is arranged so as to permit reciprocation of the pushrud 14 whenthe pump is under shuto1I pressure.

In the modification shown in FIGURE 7 the sleeve assembly 31, 32 isreplaced by a rigid tubular metal sleeve 70 which is welded at its upperend to the cover 5 and the lower end of which is press-fitted onto thecupshaped seat formed on the seat plate 4 around the inlet valve 25, anannular gasket 71 being interposed between the sleeve 70 and thecup-shaped seat on the seat piate 4.

FIGURE 8 shows a method of ensuring a fiuid tight seal between the cover5, seat plate 4, diaphragm 3 and pump body 1, in which an annular gasket8!! is interposed between the crimped over edge 6 of the cover 5 and theedge of the seat plate 4, the seal between the seat plate 4 and the seat2 on the pump body 1 being formed by the peripheral portion of thediaphragm 3 which is also clamped with the gasket and seat plate 4 bythe crimped over portion of the cover 5.

An alternative construction for ensuring the seal between the cover 5,seat plate 4, diaphragm 3 and pump holy 1 is shown in FIGURE 9, the seatplate 4 in this construction being formed with an annular bead whichabuts the cover 5 and the latter also being formed with an annularshoulder 91 which engages the peripheral edge of the seat plate 4 belowthe head 90 so as to press the latter into sealing contact with theperipheral portion of the diaphragm 3 overlying the seat 2 of thebody 1. The crimped over portion 6 of the cover 5 in addition toensuring such sealing contact between the seat plate 4 and diaphragm 3also clamps the extreme outer peripheral portion of the diaphragm 3 intosealing contact between the cover 5 and the seat 2.

We claim:

1. A diaphragm pump having a body and a flexible diaphragm the peripheryof the latter being pressed into sealing engagement with a seat on saidpump body by means of a valve and seat plate assembly shaped from sheetmaterial, a sheet metal cover retaining said diaphragm periphery andvalve and seat plate assembly in position on said pump body, inlet andoutlet valves mounted on said valve and seat plate assembly, a resilientsleeve extending around one of said valves and dividing space definedbetween said cover and valve plate into an inlet and an outlet chamber,a rigid sleeve arranged within the said resilient sleeve, and saidsleeves cooperating to define at least one air pocket between theirfacing walls, and said air pocket being adapted to act as a pulsatorchamber.

2. A pump having a valve and seat plate assembly supporting inlet andoutlet valves, a cover cooperating with said seat plate assembly todefine inlet and outlet chambers, a pump body, a pumping diaphragm, thelatter being interposed between aid pump body and said seat plateassembly to define a pumping chamber, two sleeves with coaxial facingwalls surrounding one of said valves and separating said inlet andoutlet chambers, one of said sleeves being yieldable to a greater extentthan the other and at least one air pocket being defined between thesaid facing waits 01 said sleeves.

References Cited FOREIGN PATENTS 2/ 1960 France. 9/ 1962 France. 1 l/1964 France.

DONLEY J. STOCKING, Primary Examiner.

WILLIAM L. FREEH, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,364,870 January 23, 1968 Claude Quatredeniers et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2, line 14, for "diaphragm 3 clamped therebetween. The upperplate 7" read diaphragm assembly of the pump;

Signed and sealed this 18th day of March 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3,364,870 January 23, 1968 Claude Quatredeniers et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected be1ow.

Column 2, line 14, for "diaphragm 3 clamped therebetween.

The upper plate 7" read diaphragm assembly of the pump;

Signed and sealed this 18th day of March 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

